High-throughput biochemical assays often use of unitary strips of 8 reaction tubes, which ordinarily are loaded into wells in a tube rack for processing. In some apparatus, four such tube racks are processed simultaneously. In use, the operator loads a strip of capped tubes into the tube rack and removes the strip of caps manually by pulling on the tab to lift the caps progressively from the tubes at one end to the other. The tubes are then loaded with the appropriate reagents, usually with a micropipette, and recapped by hand. The procedure of uncapping and recapping is repeated after the process (e.g., DNA amplification) to remove the samples for analysis.
If the tubes are empty, the act of removing the strip of caps in rapid succession obviously does not present any problem of ejecting contents from the tubes. However, when it becomes necessary to uncap the tubes that are full or partially full (as in the case of tubes purchased pre-packaged with reagents), it is often the case that some of the contents will be released. Furthermore, recapping the tubes also might result in spillage of some of the contents from the tubes. To minimize spillage, the technician will typically need to carefully remove and/or replace one cap at a time, which is not only tedious and time consuming, but also requires repetitive movements. Moreover, practice has shown that the closely packed tubes in the tube rack are difficult to recap manually. A careless or hurried technician may not always get all of the tubes properly recapped, which may result in test failures due to evaporation or contamination. Removing strips of caps by hand also can result in stretching of the strip, making recapping subject to failure. There exists a need for an improved method to decap and recap tubes.